This invention relates to a vehicle dynamic control system, wherein a vehicle movement control device of said system alters the vehicle's control characteristic according to the curvature of a road to be traveled.
Recently developed and put into practical use are several kinds of vehicle movement control devices, e.g., a brake control device which improves a vehicle's running stability by applying braking force to an appropriate wheel considering reaction forces while cornering or the like, a left/right-wheel-differential limiter control device which controls limitation of the differential of the left and right wheels depending on running conditions and a power distribution control device which distributes driving torque to front and rear wheels in predetermined ratios by controlling the differential limitation of a center differential based on running conditions.
For example, Japanese Patent Laid-open No. 70561/1990 disclosed a brake control device which compares an aimed yaw rate with a real yaw rate of a vehicle, judges the vehicle dynamic characteristic as under steering or over steering against the aimed yaw rate, and then applies corrective braking force to an outer wheel when judged as over steering is judged or to an inner wheel when judged as under steering is judged so that the real yaw rate and the aimed yaw rate become equal, thus upgrading the vehicle running stability.
Because the functions of the vehicle movement control devices aforementioned are corrective controls after detection of running conditions which occur presently, i.e., controls to stabilize the vehicle movement that are carried out upon detection of occurrence of unstable runs, they have difficulties in themselves to prevent occurrence of the unstable runs.
Thinking about a case where a driver finds a curved road in front while driving a vehicle equipped with one of the current vehicle movement control devices, all the measures to be taken for engaging the curved road are entrusted to the driver. If the vehicle enters onto the curved road with inappropriate measures taken by the driver, unstable runs occur and the vehicle movement control devices work thereafter, i.e., delaying the control.